In the technical field of the wire transmission such as the telecommunication, cable TV and monitoring system, the fiber-optic cable is widely used for transmitting audio, data and video messages. The fiber-optic cable transmits messages to any designated location with the assistance of a cable splice enclosure to operate a connection and a splice of the cables.
The conventional fiber-optic cable is mostly used as an intermediate backbone cables. The cable splice enclosure is mostly used for a linear splice operation and a branching splice operation. The linear splice operation is an operation of connecting a truncated cable with one other cable having cores of same quantity therein. The branching splice operation is an operation of connecting a cable having more cores with a number of other cables having less cores therein. Comparatively, the present communication network has stepped into a wide band service era of fiber-to-the-home (FTTH). Massive fiber-optic fibers must be distributed to the optic equipments at user' sides by utilizing cable splice enclosures. Therefore, the cable splice enclosures are applicable not only to the linearly splice and the branching splice operation, but also necessarily applicable to an intermediately introduced branch splice operation for massive fiber-optic cables, which is an operation for further connecting some small quantity of unused cables split from a backbone cable with multi-core optical fibers in the middle portion via a cable splice enclosure to one other intermediate splice cable for connection to a new user side when a fiber-optic cable service is required for a customer. In most of such cases, the backbone fiber-optic cable, especially the fiber-optic cable in use, cannot be cut off.
In the prior art, the methods of waterproof treatment to an end surface of a cable splice enclosure allowing cables to pass therethrough for a direct splice or a branching splice operation include three types: the mechanical type, the heat-shrinkable type, and the elastic shrinkable tube type. The components of the mechanical type is complicated and of a high cost. The cost of the heat-shrinkable type is comparatively low. However, the heat-shrinkable type has some disadvantages of, for example, a necessity to use the torching when under construction, a difficulty of controlling a consistent quality, an adverse influence to water-proof effect caused by cable shaking and distortion, and a bad qualification inadequate to an underground fiber-optic cable installed in a manhole where water is accumulative all the year round although it is adequate to be used in a hanged or a wall-mounted environment. On the contrary, the elastic shrinkable tube type is the most convenient for the construction. Besides, the elastic shrinkable tube type also has the advantages of a highly consistent construction quality, an excellent water-proof effect, and a low cost of materials. Therefore, the adoption of the elastic shrinkable tube for performing the waterproof treatment to either the cables of a direct splice operation or those of a branching splice operation is the best choice for the constructor.
The elastic shrinkable tube is made of an elastic object having the qualities of a high elongation, a high tensile strength, and an excellent restoring rate. A hard tubular plastic object having a spiral shape extractable in a stripe manner from the internal side of the elastic shrinkable tube for enlarging the inside diameter is inserted in the elastic shrinkable tube. The method for waterproof treatment by using an elastic shrinkable tube is performed as follows. Firstly, put a portion of the elastic shrinkable tube with the enlarged inside diameter to cover the outer portion of the hollow cylindrical tube disposed on an end surface for a fiber-optic cable to pass therethrough, and put the other portion of the elastic shrinkable tube to cover the portion of the fiber-optic cable passing therethrough, connecting to and lying externally to the hollow cylindrical tube. After extracting the hard tubular plastic object having a spiral shape inserted inside the elastic shrinkable tube, the inside diameter of the elastic shrinkable tube restores back to a small inside diameter originally in the situation before it was enlarged. The small inside diameter is less than both the outside diameter of the hollow cylindrical tube and that of the fiber-optic cable, so that a shrinkage force in the diametrical direction is exerted on the outer portion of the hollow cylindrical tube and the portion of the fiber-optic cable lying externally to the hollow cylindrical tube, and a tight water-proof structure is formed accordingly.
In the prior art, however, the suitable water-proof methods for the cable splice enclosures using an end surface passing therethrough a fiber-optic cable going to be operated by a branch splicing of an intermediately introduced connection merely include two types: the mechanical type and the thermal shrinkable type. The reason why an elastic shrinkable tube for water-proof treatment cannot be used for an intermediately introduced branching splice operation of a fiber-optic cable is that, while preparing a fiber-optic cable for an intermediately introduced branching splice operation, it is necessary to be under the conditions that the fiber-optic cables and cores contained therein cannot be cut off, and that the fiber-optic cable has to be in a dual-cable manner to go into the above-mentioned cable splice enclosures for a connection and a splice operations. However, an elastic shrinkable tube, after shrinking, is difficult to tightly cover the interstice formed between the dual cables so that the waterproof effect cannot be achieved. Besides, there are specific technical standards for the bending of the fiber-optic cable. Generally, the bending curvature of an outdoor fiber-optic cable allows 3 mm in radius, which is 6 mm in diameter. Therefore, for the diameter of a hole of the hollow cylindrical tube for passing therethrough the fiber-optic cable in a dual-cable manner, the inside diameter of the longer side is larger than 6 mm based on the requirements of the general telecommunication supplier. However, the diameter of a general fiber-optic cable is merely 1.5 to 2 mm so that there will be a big breach between the rim of the hole and the fiber-optic cable. That is why it is not suitable to adopt an elastic shrinkable tube to perform the water-proof treatment. Thus, for the cable splice enclosures of the prior art, the water-proof treatment of the elastic shrinkable tube type can only be used for the direct splice and the branching splice operations, while the water-proof treatment of the heat-shrinkable type or the mechanical type should be used for the branch splicing of an intermediately introduced connection.
Therefore, if there is a feasible solution to improve the cable splice enclosure of the prior art so that a cable can pass through an end surface of a cable splice enclosure and a hollow cylindrical tube disposed thereon in a dual-cable manner, an elastic shrinkable tube is possibly used for the waterproof treatment. If the method of cable splice operation using the cable splice enclosure and waterproof treatment is feasibly standardized, not only the quality and safety of the construction are improved, but also the manufacturing and maintenance cost of the constructor are greatly lowered.
In order to overcome the drawbacks in the prior art, a cable splice enclosure is provided. The particular design in the present invention not only solves the problems described above, but also is easy to be implemented. Thus, the present invention has the utility for the industry.